Stent-graft limb deployment in the external iliac artery increases the risk of limb occlusion following endovascular AAA repair.

PURPOSE: To assess whether deployment of an endograft limb in the external iliac artery (EIA) increases the rate of limb occlusion following endovascular aneurysm repair (EVAR). METHODS: Interrogation of a prospectively maintained database identified 661 patients (596 men; median age 73 years, range 37-93) with infrarenal abdominal aortic aneurysm who underwent EVAR between 1996 and 2010 using Zenith stent-grafts predominately. Of these, 567 patients [56 (9.9%) women] had both endograft limbs deployed in the CIA (1203 limbs at risk), while 94 patients [9 (9.6%) women] had at least 1 limb in the EIA (22 bilateral; 116 limbs at risk). An adjunctive bare metal stent was used in 8 (9%) limbs deployed in the EIA. RESULTS: There were 31 limb occlusions, all unilateral: 17 (3%) patients in the CIA group had an occluded limb (1% of limbs at risk) vs. 14 (15%) patients in the EIA group (12% of limbs at risk; p<0.0001). The median time to occlusion was 3 months (0-60) in the CIA group and 1 month (0-36) in the EIA group. The majority of occlusions were treated by extra-anatomical revascularization, most often a femorofemoral crossover bypass. No legs were amputated following occlusion of a limb placed in the CIA, but there were 3 amputations in the EIA group (p=0.003). CONCLUSION: Deployment of endograft limbs into the EIA led to a higher rate of occlusion and leg amputation. Increased tortuosity of the EIA and a smaller caliber vessel are likely to account for the increased risk.

Endovascular treatment of acute aortic syndrome.

BACKGROUND: The term acute aortic syndrome (AAS) encompasses a range of conditions that have a risk of imminent aortic rupture and where delays in treatment result in increased mortality. Endovascular treatment offers an attractive alternative to open surgery but little is known about the durability of the repair and the factors that predict mortality. METHODS: Prospective data were collected for a cohort of 110 consecutive patients with endovascular treatment for AAS. Patient and procedural characteristics were related to short- and midterm outcome using multivariate logistic regression analysis. RESULTS: There were 75 men and 35 women with a median age of 68 (range 57-76) years. The pathologies treated were acute dissection (35), symptomatic aneurysm (32), infected aneurysm (18), transection (12), chronic dissection (9), penetrating ulcer (3), and intramural hematoma (1). Thirty-day mortality was 12.7% and this was associated with hypotension (odds ratio [OR], 5.25), use of general anesthetic (OR, 5.23), long procedure duration (OR, 2.03), and increasing age (OR, 1.07). The causes of death were aortic rupture (4), myocardial infarction (4), stroke (3), and multisystem organ failure (3). The stroke and paraplegia rates were 7.3% and 6.4%, respectively. The 1-year survival was 81% and the 5-year survival 63%. Secondary procedures were required in 13 (11.8%) patients. Factors associated with death at 1 year were presence of an aortic fistula (OR, 9.78), perioperative stroke (OR, 5.87), and use of general anesthetic (OR, 3.76); and at 5 years were aortic fistula (OR, 12.31) and increasing age (OR, 1.06). CONCLUSIONS: Acute aortic syndrome carries significant early and late mortality. Emergency endovascular repair offers a minimally invasive treatment option associated with acceptable short and midterm results. Continued surveillance is important as secondary procedures and aortic-related deaths continue to occur throughout the follow-up period.

Feasibility and limitations of an automated 2D-3D rigid image registration system for complex endovascular aortic procedures.

PURPOSE: To examine the feasibility of an automated 2-dimensional (2D) to 3- dimensional (3D) image registration system to simplify the navigational challenges faced in complex endovascular aortic procedures. METHODS: An automated 2D-3D image registration system was used to overlay pre-acquired 3D computed tomography images onto fluoroscopy images taken during endovascular aneurysm repair. Errors between the 3D overlay and digital subtraction angiograms were measured and correlated with aortic neck angulation. A mean discrepancy < or =3 mm was considered clinically acceptable. RESULTS: There was a strong correlation between maximum neck angulation and maximum registration error (Pearson's r = 0.75). Aortas with a maximum neck angulation < or =30 degrees had a mean error of 2.5+/-1.2 mm, whereas aortas with neck angulation >30 degrees had a mean error of 6.2+/-2.5 mm (p<0.0001). CONCLUSION: The major source of registration errors is aortic deformation caused by the presence of the introducer and endovascular graft. Further work is required if this technology is to be routinely applied to severely angulated aortic anatomy.

Endovascular repair of a tuberculous mycotic thoracic aortic aneurysm with a custom-made device.

Mycotic aortic aneurysms are rare and it is unlikely that any center will obtain extensive experience in their management. The aim of treatment is to repair the aorta and eradicate the infection with minimal operative and postoperative risk. We describe a case in which a custom-made endovascular stent graft provided the optimal treatment strategy and remained durable at 4 years of follow-up.

Results of endovascular repair of abdominal aortic aneurysms with an unfavorable proximal neck using large stent-grafts.

The purpose of this study was to evaluate the early outcome of endovascular repair of abdominal aortic aneurysms (EVAR) with an unfavorable neck anatomy using extralarge stent-grafts. We carried out a retrospective review of all patients who underwent elective EVAR using large diameter stent-grafts between June 2006 and February 2008. All patients had computed tomography angiography (CTA) for procedure planning, and detailed assessment of the aneurysm neck was performed using a three-dimensional CTA workstation. All patients were followed up with CTA at 3 and 12 months and annual duplex thereafter when appropriate. This analysis included 25 patients (23 men, 2 woman; median age, 76 years; age range, 60-88 years). The median aneurysm diameter was 7 cm, and the median aneurysm neck diameter was 31 mm. Extralarge Cook-Zenith stent-grafts were used in all patients, with a top-end diameter of 36 mm (n=23) and 40 mm (n=2). The follow-up period ranged from 3 to 24 months, with a median of 6 months. Primary and assisted primary technical success rates were 80% and 96%, respectively. Reintervention was required to treat proximal type I endoleak (n=1), iliac limb kink (n=2), and occluded femorofemoral crossover graft (n=1). These early results show that EVAR using extralarge stent-grafts with suprarenal fixation can be a reliable modality to treat infrarenal aortic aneurysms with an unfavorable neck anatomy.

Intraluminal thrombus enhances proteolysis in abdominal aortic aneurysms.

This study examined whether intraluminal thrombus in abdominal aortic aneurysms (AAAs) is a source of fibrinolytic activity and proteolysis that could weaken the aneurysm wall. Plasmin, tissue plasminogen activator (tPA), and urokinase plasminogen activator (uPA) activity, plasminogen activator inhibitor 1 (PAI-1), and alpha2-antiplasmin (alpha2AP) antigen were measured in the AAA wall and juxtamural and luminal aspects of intraluminal thrombus in 18 patients. The aneurysm wall contained 100-fold higher tPA activity (1.06 +/- 0.34 [standard error of measurement] U/mg soluble protein) compared with juxtamural thrombus (JMT) (0.011 +/- 0.001 ) and luminal thrombus (LT) (0.01 +/- 0.001) (p < .00001) and over 6-fold higher uPA activity (29.3 +/- 3.4 IU/mg compared with the JMT (4.3 +/- 2.4, p = .00024) and LT (7.9 +/- 1.76, p = .0005). The LT had significantly lower levels of PAI-1 (1.26 +/- 0.34 ng/mg) than the AAA wall (2.08 +/- 0.51, p = .04) and the JMT (3.94 +/- 0.85, p = .007). The levels of alpha2AP in the wall (19.4 +/- 3.1 ng/mg) were lower than in the JMT or LT (43.0 +/- 7.9 ng/mg, p = .013, and 47.6 +/- 6.0 ng/mg, p = .002, respectively). There was no significant difference, however, in plasmin activity among the AAA wall, JMT, and LT. There were significant amounts of latent gelatinase B (matrix metalloproteinase [MMP]-9) in the AAA, JMT, and LT. Mean levels of activated MMP-9 activity were similar in the AAA, JMT, and LT. Plasmin activation of MMPs at the interface between intraluminal thrombus and the aneurysm wall may enhance proteolysis and accelerate aneurysm expansion.

Stromelysin-1 (matrix metalloproteinase-3) and tissue inhibitor of metalloproteinase-3 are overexpressed in the wall of abdominal aortic aneurysms.

BACKGROUND: Atherosclerosis is implicated in the pathogenesis of abdominal aortic aneurysm (AAA) but more often causes aortic occlusive disease (AOD). The matrix metalloproteinases (MMPs) degrade extracellular matrix and may play a central role in the pathogenesis of AAA. The aim of this study was to examine differences in the patterns of MMP and MMP inhibitor expression between AAA and AOD. METHODS AND RESULTS: The expression of mRNA for 14 MMPs and 4 tissue inhibitors of metalloproteinases (TIMPs) was estimated in samples of aortic wall from 8 patients with AAA and 8 with AOD using the reverse-transcriptase polymerase chain reaction with a synthetic multicompetitor standard. AAA wall expressed significantly more stromelysin-1 (MMP-3) (mean log(10) ratio [copy enzyme cDNA/copy GAPDH cDNA], -1.9; range, -3.3 to -0.7) than the AOD wall (mean, 4; range, -5.7 to -2.4), P<0.005. TIMP-3 expression was significantly higher in AAA (mean, -1.7; range, -2.9 to -1.0) than AOD (mean, -3.6; range, -5.7 to -1.8), P<0.01. Expression of 8 other MMPs (1, 2, 7, 9, 11, 12, 14, and 17) was detected and was similar in AAA and AOD. Expression of the remaining 5 MMPs (-8, -10, -13, -15, and -16) was not detected in any of the samples. CONCLUSIONS: Both AAA and AOD walls express similar levels of a wide range of MMPs, including cell membrane-bound MT-MMPs. Stromelysin-1 (MMP-3) and TIMP-3 were, however, over expressed in the AAA samples and may be involved aneurysm pathogenesis. Stromelysin-1 could provide a target for pharmacological inhibition.